CRIME IN AMERICA:LET’S CLEAN UP THE

STREETS!

Chris Blees

Conner Faught

Ryan Shaffer

VIOLENT CRIME IN AMERICA

• Question: What factors lead to violent crime and do those factors vary by the size of the city?– Factors Examined:

• Percentage of Population Under the Poverty Line

• People per Family

• Distance from State Capitol

• Size of Police Force

• High School Graduation Rate

• Annual Precipitation

• Divorce Rate

• Average Travel Time to Work

• Percentage of Population that are Civilian Veterans

• Median Age

CITIES USED IN ANALYSIS• 250,000+

Atlanta, GAAurora, COBuffalo, NYPhoenix, AZPittsburgh, PATampa, FAToledo, OHSanta Ana, CAOakland, CAArlington, TX

• 100,000-250,000Richmond, VASan Bernardino, CASt. Petersburg, FAPortsmouth, VACharleston, SCPaterson, NJWestminster, COOrange, CABirmingham, ALSyracuse, NY

• 60,000-100,000Upper Darby Township, PATustin, CATuscaloosa, ALTracy, CATemecula, CASugar Land, TXBeaverton, ORBellflower, CAClifton, NJColumbia, MO

• 20,000-60,000Ames, IAAnderson, INBinghamton, NYBloomfield, NJBowling Green, KYBullhead City, AZGreenburgh Town, NYHendersonville, TNKirkland, WAMansfield, TX

DESCRIPTIVE STATISTICSMean Median Std Deviation Minimum Maximum Count

Under Poverty Line 15.33 16.1 7.680384606 3.9 31 40

People/Family 3.19225 3.105 0.345465034 2.8 4.72 40

Distance from State Capitol 134.5 99.5 125.9910457 0 426 40

Police Officers 421.425 166 569.313842 49 3220 40

HS Graduation % 65.36 65.95 16.33301417 31.2 90.1 40

Precipitation 34.21 38.8 15.08809685 4.7 55 40

% Divorced 10.2675 10.7 2.70871222 4.2 15.1 40

Time to Work 24.595 24 5.448262485 15 41.9 40

% Civilian Veterans 11.49 11.55 3.081441554 5 20.8 40

Median Age 33.065 33.2 3.855435723 23.6 41.8 40

EXPECTED RESULTS

Independent Variable Expected Relationship

Percentage of Population Under the Poverty Line

Positive

People Per Family Positive

Distance From State Capitol Positive

Size of Police Force Negative

High School Graduation Rate Negative

Annual Precipitation Positive

Divorce Rate Positive

Average Travel Time to Work Negative

Percentage of Population that are Civilian Veterans

Negative

Median Age Negative

REGRESSION ANALYSIS

Regression Statistics

Multiple R 0.883752474

R Square 0.781018435

Adjusted R Square 0.70550755

Standard Error 244.764056

Observations 40

ANOVA

  df SS MS F Significance F

Regression 10 6196507.9 619650.7925 10.343 3.76919E-07

Residual 29 1737373.85 59909.4431

Total 39 7933881.775      

REGRESSION ANALYSIS, CONT.

  Coefficients Standard Error t Stat P-value

Intercept 995.1355138 1269.084842 0.784136317 0.439318415

% under Poverty Line 28.59096442 10.17992151 2.808564329 0.008813091

Average Number of People/Family -261.5593937 231.4495346 -1.130092545 0.267697831

Distance From State Capital(Miles) 0.634059133 0.427380986 1.483592282 0.14870513

Police Officers (2008) 0.156190091 0.085406716 1.828779961 0.077734615

High School Graduates (Percentage) -9.912498362 4.127235369 -2.401728391 0.022949078

Average Precipitation (inches) 6.874069669 3.886549608 1.768681829 0.087465669

% population divorced 34.65590142 21.0148204 1.649117183 0.109916154

mean travel time to work 27.86069548 12.24140536 2.275939295 0.030416635

% of population that are civilian veterans -44.10999457 20.55095204 -2.146372318 0.040341187

median age -6.946041193 14.88362894 -0.466690027 0.644208808

LINEAR RESULTS

Independent Variable Expected Relationship

Percentage of Population Under the Poverty Line

Positive

People Per Family Negative

Distance From State Capitol Positive

Size of Police Force Positive

High School Graduation Rate Negative

Annual Precipitation Positive

Divorce Rate Positive

Average Travel Time to Work Positive

Percentage of Population that are Civilian Veterans

Negative

Median Age Negative

VALIDITYBecause the test for homoscedasticity for the predicted values versus the residuals produces a notable ovoid shape, and because the histogram of the residuals produced a curve with a normal, bell-curve shape, the model appears to be valid.

CONCLUSIONS

• Of the factors we chose, only four had a significant impact on violent crime rates nationwide.

– Percentage of the population under the poverty line.

– High school graduation rate.

– Mean travel time to work.

– Percentage of the population that are civilian veterans.

• Possible limitations of our model could include:

– Small sample size (40 cities).

– Data taken from 2000.

– Only examines violent crimes.

SOURCES

• http://www.city-data.com/

• 2000 U.S. Census

• Bureau of Justice Statistics